#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include <stm32f4xx_hal.h>

#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "misc.h"
#include "lexer.h"
#include "parse.h"
#include "obj.h"
#include "parsehelper.h"
#include "compile.h"
#include "runtime.h"
#include "repl.h"
#include "gc.h"
#include "gccollect.h"
#include "systick.h"
#include "pyexec.h"
#include "storage.h"
#include "usb.h"
#include "usart.h"

pyexec_mode_kind_t pyexec_mode_kind = PYEXEC_MODE_FRIENDLY_REPL;
STATIC bool repl_display_debugging_info = 0;

void stdout_tx_str(const char *str) {
    if (pyb_usart_global_debug != PYB_USART_NONE) {
        usart_tx_str(pyb_usart_global_debug, str);
    }
#if defined(USE_HOST_MODE) && MICROPY_HW_HAS_LCD
    lcd_print_str(str);
#endif
    usb_vcp_send_str(str);
}

void stdout_tx_strn(const char *str, uint len) {
    if (pyb_usart_global_debug != PYB_USART_NONE) {
        usart_tx_strn(pyb_usart_global_debug, str, len);
    }
#if defined(USE_HOST_MODE) && MICROPY_HW_HAS_LCD
    lcd_print_strn(str, len);
#endif
    usb_vcp_send_strn(str, len);
}

int stdin_rx_chr(void) {
    for (;;) {
#if 0
#ifdef USE_HOST_MODE
        pyb_usb_host_process();
        int c = pyb_usb_host_get_keyboard();
        if (c != 0) {
            return c;
        }
#endif
#endif
        if (usb_vcp_rx_num() != 0) {
            return usb_vcp_rx_get();
        } else if (pyb_usart_global_debug != PYB_USART_NONE && usart_rx_any(pyb_usart_global_debug)) {
            return usart_rx_char(pyb_usart_global_debug);
        }
        HAL_Delay(1);
        if (storage_needs_flush()) {
            storage_flush();
        }
    }
}

char *str_dup(const char *str) {
    uint32_t len = strlen(str);
    char *s2 = m_new(char, len + 1);
    memcpy(s2, str, len);
    s2[len] = 0;
    return s2;
}

#define READLINE_HIST_SIZE (8)

static const char *readline_hist[READLINE_HIST_SIZE] = {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL};

int readline(vstr_t *line, const char *prompt) {
    stdout_tx_str(prompt);
    int orig_line_len = line->len;
    int escape_seq = 0;
    int hist_cur = -1;
    int cursor_pos = orig_line_len;
    for (;;) {
        int c = stdin_rx_chr();
        int last_line_len = line->len;
        int redraw_step_back = 0;
        bool redraw_from_cursor = false;
        int redraw_step_forward = 0;
        if (escape_seq == 0) {
            if (VCP_CHAR_CTRL_A <= c && c <= VCP_CHAR_CTRL_D && vstr_len(line) == orig_line_len) {
                // control character with empty line
                return c;
            } else if (c == '\r') {
                // newline
                stdout_tx_str("\r\n");
                if (line->len > orig_line_len && (readline_hist[0] == NULL || strcmp(readline_hist[0], line->buf + orig_line_len) != 0)) {
                    // a line which is not empty and different from the last one
                    // so update the history
                    for (int i = READLINE_HIST_SIZE - 1; i > 0; i--) {
                        readline_hist[i] = readline_hist[i - 1];
                    }
                    readline_hist[0] = str_dup(line->buf + orig_line_len);
                }
                return 0;
            } else if (c == 27) {
                // escape sequence
                escape_seq = 1;
            } else if (c == 127) {
                // backspace
                if (cursor_pos > orig_line_len) {
                    vstr_cut_out_bytes(line, cursor_pos - 1, 1);
                    // set redraw parameters
                    redraw_step_back = 1;
                    redraw_from_cursor = true;
                }
            } else if (32 <= c && c <= 126) {
                // printable character
                vstr_ins_char(line, cursor_pos, c);
                // set redraw parameters
                redraw_from_cursor = true;
                redraw_step_forward = 1;
            }
        } else if (escape_seq == 1) {
            if (c == '[') {
                escape_seq = 2;
            } else {
                escape_seq = 0;
            }
        } else if (escape_seq == 2) {
            escape_seq = 0;
            if (c == 'A') {
                // up arrow
                if (hist_cur + 1 < READLINE_HIST_SIZE && readline_hist[hist_cur + 1] != NULL) {
                    // increase hist num
                    hist_cur += 1;
                    // set line to history
                    line->len = orig_line_len;
                    vstr_add_str(line, readline_hist[hist_cur]);
                    // set redraw parameters
                    redraw_step_back = cursor_pos - orig_line_len;
                    redraw_from_cursor = true;
                    redraw_step_forward = line->len - orig_line_len;
                }
            } else if (c == 'B') {
                // down arrow
                if (hist_cur >= 0) {
                    // decrease hist num
                    hist_cur -= 1;
                    // set line to history
                    vstr_cut_tail_bytes(line, line->len - orig_line_len);
                    if (hist_cur >= 0) {
                        vstr_add_str(line, readline_hist[hist_cur]);
                    }
                    // set redraw parameters
                    redraw_step_back = cursor_pos - orig_line_len;
                    redraw_from_cursor = true;
                    redraw_step_forward = line->len - orig_line_len;
                }
            } else if (c == 'C') {
                // right arrow
                if (cursor_pos < line->len) {
                    redraw_step_forward = 1;
                }
            } else if (c == 'D') {
                // left arrow
                if (cursor_pos > orig_line_len) {
                    redraw_step_back = 1;
                }
            }
        } else {
            escape_seq = 0;
        }

        // redraw command prompt, efficiently
        if (redraw_step_back > 0) {
            for (int i = 0; i < redraw_step_back; i++) {
                stdout_tx_str("\b");
            }
            cursor_pos -= redraw_step_back;
        }
        if (redraw_from_cursor) {
            if (line->len < last_line_len) {
                // erase old chars
                for (int i = cursor_pos; i < last_line_len; i++) {
                    stdout_tx_str(" ");
                }
                // step back
                for (int i = cursor_pos; i < last_line_len; i++) {
                    stdout_tx_str("\b");
                }
            }
            // draw new chars
            stdout_tx_strn(line->buf + cursor_pos, line->len - cursor_pos);
            // move cursor forward if needed (already moved forward by length of line, so move it back)
            for (int i = cursor_pos + redraw_step_forward; i < line->len; i++) {
                stdout_tx_str("\b");
            }
            cursor_pos += redraw_step_forward;
        } else if (redraw_step_forward > 0) {
            // draw over old chars to move cursor forwards
            stdout_tx_strn(line->buf + cursor_pos, redraw_step_forward);
            cursor_pos += redraw_step_forward;
        }

        HAL_Delay(1);
    }
}

// parses, compiles and executes the code in the lexer
// frees the lexer before returning
bool parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, bool is_repl) {
    mp_parse_error_kind_t parse_error_kind;
    mp_parse_node_t pn = mp_parse(lex, input_kind, &parse_error_kind);
    qstr source_name = mp_lexer_source_name(lex);

    if (pn == MP_PARSE_NODE_NULL) {
        // parse error
        mp_parse_show_exception(lex, parse_error_kind);
        mp_lexer_free(lex);
        return false;
    }

    mp_lexer_free(lex);

    mp_obj_t module_fun = mp_compile(pn, source_name, is_repl);
    mp_parse_node_free(pn);

    if (module_fun == mp_const_none) {
        return false;
    }

    nlr_buf_t nlr;
    bool ret;
    uint32_t start = HAL_GetTick();
    if (nlr_push(&nlr) == 0) {
        usb_vcp_set_interrupt_char(VCP_CHAR_CTRL_C); // allow ctrl-C to interrupt us
        rt_call_function_0(module_fun);
        usb_vcp_set_interrupt_char(VCP_CHAR_NONE); // disable interrupt
        nlr_pop();
        ret = true;
    } else {
        // uncaught exception
        // FIXME it could be that an interrupt happens just before we disable it here
        usb_vcp_set_interrupt_char(VCP_CHAR_NONE); // disable interrupt
        mp_obj_print_exception((mp_obj_t)nlr.ret_val);
        ret = false;
    }

    // display debugging info if wanted
    if (is_repl && repl_display_debugging_info) {
        uint32_t ticks = HAL_GetTick() - start; // TODO implement a function that does this properly
        printf("took %lu ms\n", ticks);
        gc_collect();
        // qstr info
        {
            uint n_pool, n_qstr, n_str_data_bytes, n_total_bytes;
            qstr_pool_info(&n_pool, &n_qstr, &n_str_data_bytes, &n_total_bytes);
            printf("qstr:\n  n_pool=%u\n  n_qstr=%u\n  n_str_data_bytes=%u\n  n_total_bytes=%u\n", n_pool, n_qstr, n_str_data_bytes, n_total_bytes);
        }

        // GC info
        {
            gc_info_t info;
            gc_info(&info);
            printf("GC:\n");
            printf("  %lu total\n", info.total);
            printf("  %lu : %lu\n", info.used, info.free);
            printf("  1=%lu 2=%lu m=%lu\n", info.num_1block, info.num_2block, info.max_block);
        }
    }

    return ret;
}

int pyexec_raw_repl(void) {
    vstr_t line;
    vstr_init(&line, 32);

raw_repl_reset:
    stdout_tx_str("raw REPL; CTRL-B to exit\r\n");

    for (;;) {
        vstr_reset(&line);
        stdout_tx_str(">");
        for (;;) {
            char c = stdin_rx_chr();
            if (c == VCP_CHAR_CTRL_A) {
                // reset raw REPL
                goto raw_repl_reset;
            } else if (c == VCP_CHAR_CTRL_B) {
                // change to friendly REPL
                stdout_tx_str("\r\n");
                vstr_clear(&line);
                pyexec_mode_kind = PYEXEC_MODE_FRIENDLY_REPL;
                return 0;
            } else if (c == VCP_CHAR_CTRL_C) {
                // clear line
                vstr_reset(&line);
            } else if (c == VCP_CHAR_CTRL_D) {
                // input finished
                break;
            } else if (c == '\r') {
                vstr_add_char(&line, '\n');
            } else if (32 <= c && c <= 126) {
                vstr_add_char(&line, c);
            }
        }

        // indicate reception of command
        stdout_tx_str("OK");

        if (line.len == 0) {
            // exit for a soft reset
            stdout_tx_str("\r\n");
            vstr_clear(&line);
            return 1;
        }

        mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, line.buf, line.len, 0);
        parse_compile_execute(lex, MP_PARSE_FILE_INPUT, false);

        // indicate end of output with EOF character
        stdout_tx_str("\004");
    }
}

int pyexec_friendly_repl(void) {
    vstr_t line;
    vstr_init(&line, 32);

#if defined(USE_HOST_MODE) && MICROPY_HW_HAS_LCD
    // in host mode, we enable the LCD for the repl
    mp_obj_t lcd_o = rt_call_function_0(rt_load_name(qstr_from_str("LCD")));
    rt_call_function_1(rt_load_attr(lcd_o, qstr_from_str("light")), mp_const_true);
#endif

friendly_repl_reset:
    stdout_tx_str("Micro Python build <git hash> on 25/1/2014; " MICROPY_HW_BOARD_NAME " with STM32F405RG\r\n");
    stdout_tx_str("Type \"help()\" for more information.\r\n");

    // to test ctrl-C
    /*
    {
        uint32_t x[4] = {0x424242, 0xdeaddead, 0x242424, 0xdeadbeef};
        for (;;) {
            nlr_buf_t nlr;
            printf("pyexec_repl: %p\n", x);
            usb_vcp_set_interrupt_char(VCP_CHAR_CTRL_C);
            if (nlr_push(&nlr) == 0) {
                for (;;) {
                }
            } else {
                printf("break\n");
            }
        }
    }
    */

    for (;;) {
        vstr_reset(&line);
        int ret = readline(&line, ">>> ");

        if (ret == VCP_CHAR_CTRL_A) {
            // change to raw REPL
            stdout_tx_str("\r\n");
            vstr_clear(&line);
            pyexec_mode_kind = PYEXEC_MODE_RAW_REPL;
            return 0;
        } else if (ret == VCP_CHAR_CTRL_B) {
            // reset friendly REPL
            stdout_tx_str("\r\n");
            goto friendly_repl_reset;
        } else if (ret == VCP_CHAR_CTRL_C) {
            // break
            stdout_tx_str("\r\n");
            continue;
        } else if (ret == VCP_CHAR_CTRL_D) {
            // exit for a soft reset
            stdout_tx_str("\r\n");
            vstr_clear(&line);
            return 1;
        } else if (vstr_len(&line) == 0) {
            continue;
        }

        if (mp_repl_is_compound_stmt(vstr_str(&line))) {
            for (;;) {
                vstr_add_char(&line, '\n');
                int len = vstr_len(&line);
                int ret = readline(&line, "... ");
                if (ret == VCP_CHAR_CTRL_D || vstr_len(&line) == len) {
                    // done entering compound statement
                    break;
                }
            }
        }

        mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, vstr_str(&line), vstr_len(&line), 0);
        parse_compile_execute(lex, MP_PARSE_SINGLE_INPUT, true);
    }
}

bool pyexec_file(const char *filename) {
    mp_lexer_t *lex = mp_lexer_new_from_file(filename);

    if (lex == NULL) {
        printf("could not open file '%s' for reading\n", filename);
        return false;
    }

    return parse_compile_execute(lex, MP_PARSE_FILE_INPUT, false);
}

mp_obj_t pyb_set_repl_info(mp_obj_t o_value) {
    repl_display_debugging_info = mp_obj_get_int(o_value);
    return mp_const_none;
}

MP_DEFINE_CONST_FUN_OBJ_1(pyb_set_repl_info_obj, pyb_set_repl_info);