/**
 * @file buffer.c
 * @brief Buffer management implementation for multiple open files
 */

#include "../include/buffer.h"
#include "../include/file_io.h"
#include "../include/editor_op.h"
#include "../include/data.h"
#include "include/split_screen.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "include/input.h"

extern struct editorConfig E;

/**
 * @brief Finds a buffer by filename
 * @param filename The filename to search for
 * @return Buffer ID if found, -1 if not found
 */
static int bufferFindByFilename(const char* filename)
{
    for (int i = 0; i < E.number_of_buffer; i++)
    {
        if (E.buffers[i].filename != NULL &&
            strcmp(E.buffers[i].filename, filename) == 0)
        {
            return E.buffers[i].buffer_id;
        }
    }
    return -1;
}

/**
 * @brief Finds a buffer by ID
 * @param buffer_id The buffer ID to find
 * @return Pointer to buffer, NULL if not found
 */
struct buffer_t* bufferFindById(int buffer_id)
{
    for (int i = 0; i < E.number_of_buffer; i++)
    {
        if (E.buffers[i].buffer_id == buffer_id)
        {
            return &E.buffers[i];
        }
    }
    return NULL;
}

/**
 * @brief Creates a new buffer for a file
 * @details Allocates buffer slot, loads file content, saves buffer metadata.
 * If file is already open, switches to existing buffer instead.
 * @param filename Path to the file
 * @return Buffer ID on success, -1 on failure
 */
int bufferCreate(const char* filename)
{
    // Check if file is already open
    const int existing_id = bufferFindByFilename(filename);
    if (existing_id != -1)
    {
        return bufferSwitch(existing_id);
    }

    // Check if we have space for more buffers
    if (E.number_of_buffer >= 64)
    {
        editorSetStatusMessage("Error: maximum buffers reached (64)");
        return -1;
    }

    // Initialize new buffer
    struct buffer_t* new_buf = &E.buffers[E.number_of_buffer];
    new_buf->buffer_id = E.number_of_buffer;
    new_buf->filename = strdup(filename);
    new_buf->type = FILE_BUFF;
    new_buf->state = READ_AND_WRITE;
    new_buf->x = 0;
    new_buf->y = 0;
    new_buf->dirty = 0; // New file starts clean

    // Load file content using existing editorOpen
    editorOpen(new_buf);

    E.number_of_buffer++;

    editorSetStatusMessage("Opened: %s (buffer %d)", filename, new_buf->buffer_id);
    return new_buf->buffer_id;
}

/**
 * @brief Switches to a specific buffer by ID
 * @details Saves current buffer state, loads target buffer content and state.
 * @param buffer_id The buffer ID to switch to
 * @return 0 on success, -1 on failure
 */
int bufferSwitch(int buffer_id)
{
    struct buffer_t* target = bufferFindById(buffer_id);
    if (target == NULL)
    {
        E.layout.panes[E.layout.active_pane].buffer_id = buffer_id;
        editorSetStatusMessage("Error: buffer not found");
        return -1;
    }


    editorSetStatusMessage("Switched to: %s (buffer %d)",
                           target->filename, buffer_id);
    return 0;
}

/**
 * @brief Closes a buffer by ID
 * @details Frees buffer resources and removes from buffer list.
 * Prompts to save unsaved changes. If closing current buffer,
 * switches to next available buffer.
 * @param buffer_id The buffer ID to close
 * @return 0 on success, -1 on failure
 */
int bufferClose(int buffer_id)
{
    struct buffer_t* buf = bufferFindById(buffer_id);
    if (buf == NULL)
    {
        editorSetStatusMessage("Error: buffer not found");
        return -1;
    }

    EditorPane* active = splitScreenGetActivePane();

    // If this is the current buffer, find next buffer to switch to
    if (active->buffer_id == buffer_id)
    {
        int next_id = -1;

        // Try to switch to next buffer
        for (int i = 0; i < E.number_of_buffer; i++)
        {
            if (E.buffers[i].buffer_id != buffer_id)
            {
                next_id = E.buffers[i].buffer_id;
                break;
            }
        }

        if (next_id != -1)
        {
            bufferSwitch(next_id);
        }
        else
        {
            // No other buffers, clear editor
            editorCloseFile();
        }
    }

    // Free buffer resources
    free(buf->filename);
    buf->filename = NULL;
    buf->buffer_id = -1;

    // Remove from buffer list by shifting
    for (int i = 0; i < E.number_of_buffer; i++)
    {
        if (E.buffers[i].buffer_id == buffer_id)
        {
            for (int j = i; j < E.number_of_buffer - 1; j++)
            {
                E.buffers[j] = E.buffers[j + 1];
            }
            E.number_of_buffer--;
            break;
        }
    }

    editorSetStatusMessage("Closed buffer %d", buffer_id);
    return 0;
}

/**
 * @brief Gets the current active buffer
 * @return Pointer to current buffer_t, NULL if none
 */
struct buffer_t* bufferGetCurrent(void)
{
    EditorPane* active = splitScreenGetActivePane();
    return bufferFindById(active->buffer_id);
}

/**
 * @brief Lists all open buffers
 * @details Prints buffer information to status message
 * @return Number of open buffers
 */
int bufferListAll(void)
{
    if (E.number_of_buffer == 0)
    {
        editorSetStatusMessage("No buffers open");
        return 0;
    }

    char buf[256] = "";
    int offset = 0;
    EditorPane* active = splitScreenGetActivePane();

    for (int i = 0; i < E.number_of_buffer; i++)
    {
        struct buffer_t* b = &E.buffers[i];
        char marker = (b->buffer_id == active->buffer_id) ? '*' : ' ';
        offset += snprintf(&buf[offset], sizeof(buf) - offset,
                           "%c%d:%s ", marker, b->buffer_id,
                           b->filename ? b->filename : "[No Name]");
    }

    editorSetStatusMessage("Buffers: %s", buf);
    return E.number_of_buffer;
}

/**
 * @brief Saves current buffer to disk
 * @return 0 on success, -1 on failure
 */
int bufferSave(void)
{
    EditorPane* active = splitScreenGetActivePane();
    if (active->buffer_id == -1)
    {
        editorSetStatusMessage("Error: no buffer active");
        return -1;
    }

    editorSave();
    return 0;
}

/**
 * @brief Saves all buffers to disk
 * @details Iterates through all buffers, saves each one
 * @return 0 on success, -1 on failure
 */
int bufferSaveAll(void)
{
    int saved = 0;
    int failed = 0;

    for (int i = 0; i < E.number_of_buffer; i++)
    {
        if (bufferSwitch(E.buffers[i].buffer_id) == 0)
        {
            if (E.dirty && bufferSave() == 0)
            {
                saved++;
            }
        }
        else
        {
            failed++;
        }
    }

    editorSetStatusMessage("Saved %d buffers (%d failed)", saved, failed);
    return (failed == 0) ? 0 : -1;
}

/**
 * @brief Searches for a string in the document
 * @details Prompts user for a search query, then searches forward from current
 * cursor position. Updates cursor position to the first match found.
 * @note Updates global editor state E (cursor position, row_offset)
 * @note Search is case-sensitive and operates on rendered line content
 * @note Searches begin from the line after current cursor position
 * @see editorPrompt()
 * @see editorRowRxToCx()
 */
void bufferFind(struct buffer_t* buf)
{
    appDebug("searching\n");
    char* query = editorPrompt("Search: %s (ESC to cancel)", "", 0);
    EditorPane* active = splitScreenGetActivePane();

    if (query == NULL)
        return;
    int i;
    for (i = active->cursor_y + 1; i < buf->numrows; i++)
    {
        row_t* row = &buf->row[i];
        char* match = strstr(row->chars, query);
        if (match)
        {
            active->cursor_y = i;
            buf->y = buf->numrows;
            break;
        }
    }
    free(query);
}