#include "pms_config.h"
#include "pms_data.h"
#include "pms_ref.h"
#include "pms_render.h"
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <unistd.h>

static const char *usage_str =
    "usage: pms [flags] [reference...]\n"
    "\n"
    "Bíblia Sagrada — Tradução e Comentários do Padre Manuel de Matos Soares (1932)\n"
    "\n"
    "Flags:\n"
    "  -A num  show num verses of context after matching verses\n"
    "  -B num  show num verses of context before matching verses\n"
    "  -C      show matching verses in context of the chapter\n"
    "  -c      show Padre Matos Soares's commentaries/footnotes for matching verses\n"
    "  -e      highlighting of chapters and verse numbers\n"
    "          (default when output is a TTY)\n"
    "  -p      output to less with chapter grouping, spacing, indentation,\n"
    "          and line wrapping\n"
    "          (default when output is a TTY)\n"
    "  -W      no line wrap\n"
    "  -l      list books\n"
    "  -h      show help\n"
    "\n"
    "Reference:\n"
    "    <Book>\n"
    "        Individual book (e.g. \"Gn\", \"1Rs\", \"1Sm\", \"Mt\")\n"
    "    <Book>:<Chapter> or <Book> <Chapter>\n"
    "        Individual chapter of a book (e.g. \"Gn:1\", \"Sl 23\")\n"
    "    <Book>:<Chapter>:<Verse>[,<Verse>]...\n"
    "        Individual verse(s) of a specific chapter of a book (e.g. \"Jo 3:16\", \"Gn 1:1,3,5\")\n"
    "    <Book>:<Chapter>-<Chapter>\n"
    "        Range of chapters in a book (e.g. \"Gn 1-3\")\n"
    "    <Book>:<Chapter>:<Verse>-<Verse>\n"
    "        Range of verses in a book chapter (e.g. \"Gn 1:1-5\")\n"
    "    <Book>:<Chapter>:<Verse>-<Chapter>:<Verse>\n"
    "        Range of chapters and verses in a book (e.g. \"Gn 1:26-2:3\")\n"
    "\n"
    "    /<Search>\n"
    "        All verses that match a pattern (case- and accent-insensitive)\n"
    "    <Book>/<Search>\n"
    "        All verses in a book that match a pattern\n"
    "    <Book>:<Chapter>/<Search>\n"
    "        All verses in a chapter of a book that match a pattern\n";

static int get_terminal_width(void) {
    struct winsize ws;
    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == 0 && ws.ws_col > 0) {
        return (ws.ws_col < 80) ? ws.ws_col : 80;
    }
    return 80;
}

static FILE *open_pager(pid_t *pager_pid) {
    *pager_pid = -1;
    int pipefd[2];
    if (pipe(pipefd) != 0) {
        return stdout;
    }

    pid_t pid = fork();
    if (pid < 0) {
        close(pipefd[0]);
        close(pipefd[1]);
        return stdout;
    }

    if (pid == 0) {
        /* Child: run pager */
        close(pipefd[1]);
        if (dup2(pipefd[0], STDIN_FILENO) < 0) {
            _exit(1);
        }
        close(pipefd[0]);

        const char *pager = getenv("PAGER");
        if (pager && pager[0] != '\0') {
            execlp(pager, pager, (char *)NULL);
        }
        execlp("less", "less", "-J", "-I", "-R", "-f", "-", (char *)NULL);
        execlp("more", "more", (char *)NULL);
        _exit(1);
    }

    /* Parent */
    close(pipefd[0]);
    *pager_pid = pid;
    FILE *fp = fdopen(pipefd[1], "w");
    if (!fp) {
        close(pipefd[1]);
        *pager_pid = -1;
        return stdout;
    }
    return fp;
}

static void close_pager(FILE *fp, pid_t pager_pid) {
    if (fp && fp != stdout) {
        fclose(fp);
    }
    if (pager_pid > 0) {
        int status = 0;
        waitpid(pager_pid, &status, 0);
    }
}

static int run_query(const char *query_str, const pms_config *config, bool use_pager) {
    pms_ref *ref = pms_newref();
    if (!ref) {
        return 1;
    }
    if (pms_parse_ref(query_str, ref) != 0) {
        fprintf(stderr, "pms: referência inválida: %s\n", query_str);
        pms_freeref(ref);
        return 1;
    }

    pid_t pager_pid = -1;
    FILE *out = stdout;
    if (use_pager) {
        out = open_pager(&pager_pid);
    }

    pms_render(ref, config, out);

    if (use_pager) {
        close_pager(out, pager_pid);
    }
    pms_freeref(ref);
    return 0;
}

int main(int argc, char *argv[]) {
    bool is_tty = isatty(STDOUT_FILENO) != 0;
    signal(SIGPIPE, SIG_IGN);

    pms_config config = {
        .before_context = 0,
        .after_context = 0,
        .chapter_context = false,
        .show_notes = false,
        .highlighting = is_tty,
        .pretty = is_tty,
        .maximum_line_length = get_terminal_width(),
    };

    bool list_books = false;
    bool no_wrap = false;

    int opt;
    while ((opt = getopt(argc, argv, "A:B:CcepwWlhn")) != -1) {
        switch (opt) {
        case 'A': {
            char *endptr = NULL;
            errno = 0;
            long val = strtol(optarg, &endptr, 10);
            if (errno != 0 || endptr == optarg || *endptr != '\0' || val < 0) {
                fprintf(stderr, "pms: número inválido para -A: %s\n\n%s", optarg, usage_str);
                return 1;
            }
            config.after_context = (int)val;
            break;
        }
        case 'B': {
            char *endptr = NULL;
            errno = 0;
            long val = strtol(optarg, &endptr, 10);
            if (errno != 0 || endptr == optarg || *endptr != '\0' || val < 0) {
                fprintf(stderr, "pms: número inválido para -B: %s\n\n%s", optarg, usage_str);
                return 1;
            }
            config.before_context = (int)val;
            break;
        }
        case 'C':
            config.chapter_context = true;
            break;
        case 'c':
        case 'n':
            config.show_notes = true;
            break;
        case 'e':
            config.highlighting = true;
            break;
        case 'p':
            config.pretty = true;
            break;
        case 'W':
        case 'w':
            no_wrap = true;
            break;
        case 'l':
            list_books = true;
            break;
        case 'h':
            printf("%s", usage_str);
            return 0;
        default:
            fprintf(stderr, "\n%s", usage_str);
            return 1;
        }
    }

    if (no_wrap) {
        config.maximum_line_length = 0;
    }

    if (list_books) {
        for (int i = 0; i < pms_books_length; i++) {
            printf("%s (%s)\n", pms_books[i].name, pms_books[i].abbr);
        }
        return 0;
    }

    int rem_argc = argc - optind;
    char **rem_argv = argv + optind;

    if (rem_argc == 0) {
        /* Interactive REPL mode */
        char line[1024];
        while (true) {
            if (isatty(STDIN_FILENO)) {
                printf("pms> ");
                fflush(stdout);
            }
            if (!fgets(line, sizeof(line), stdin)) {
                if (isatty(STDIN_FILENO)) {
                    printf("\n");
                }
                break;
            }
            size_t len = strlen(line);
            while (len > 0 && isspace((unsigned char)line[len - 1])) {
                line[--len] = '\0';
            }
            char *p = line;
            while (*p && isspace((unsigned char)*p)) {
                p++;
            }
            if (*p == '\0') {
                continue;
            }
            if (strcmp(p, "q") == 0 || strcmp(p, "quit") == 0 ||
                strcmp(p, "exit") == 0 || strcmp(p, "sair") == 0) {
                break;
            }
            if (strcmp(p, ":c") == 0 || strcmp(p, "-c") == 0) {
                config.show_notes = !config.show_notes;
                printf("Comentários: %s\n", config.show_notes ? "activados" : "desactivados");
                continue;
            }
            if (strcmp(p, "-l") == 0 || strcmp(p, ":l") == 0) {
                for (int i = 0; i < pms_books_length; i++) {
                    printf("%s (%s)\n", pms_books[i].name, pms_books[i].abbr);
                }
                continue;
            }
            if (strcmp(p, "-h") == 0 || strcmp(p, ":h") == 0 || strcmp(p, "help") == 0) {
                printf("%s", usage_str);
                continue;
            }
            run_query(p, &config, is_tty && config.pretty);
        }
        return 0;
    }

    /* Join remaining CLI arguments into a single reference string */
    size_t total_len = 0;
    for (int i = 0; i < rem_argc; i++) {
        total_len += strlen(rem_argv[i]) + 2;
    }
    char *joined = malloc(total_len + 1);
    if (!joined) {
        return 1;
    }
    joined[0] = '\0';
    for (int i = 0; i < rem_argc; i++) {
        if (i > 0) {
            strcat(joined, " ");
        }
        strcat(joined, rem_argv[i]);
    }

    int rc = run_query(joined, &config, is_tty && config.pretty);
    free(joined);
    return rc;
}