package api

import (
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/restxlsx/restxlsx/internal/excel"
	"github.com/restxlsx/restxlsx/internal/logger"
)

type RestAPI struct {
	engine *excel.Engine
	log    *logger.Logger
}

func NewRestAPI(engine *excel.Engine, log *logger.Logger) *RestAPI {
	return &RestAPI{engine: engine, log: log}
}

func (h *RestAPI) ListTables(w http.ResponseWriter, r *http.Request) {
	h.engine.Lock()
	tables := h.engine.ListTables()
	h.engine.Unlock()
	writeJSON(w, 200, map[string][]string{"tables": tables})
}

func (h *RestAPI) ListRecords(w http.ResponseWriter, r *http.Request) {
	table := chi.URLParam(r, "table")
	h.engine.Lock()
	t := h.engine.GetTable(table)
	if t == nil {
		h.engine.Unlock()
		writeJSON(w, 404, map[string]string{"error": "table not found"})
		return
	}
	rows := t.Rows
	h.engine.Unlock()
	writeJSON(w, 200, rows)
}

func (h *RestAPI) GetRecord(w http.ResponseWriter, r *http.Request) {
	table := chi.URLParam(r, "table")
	id := chi.URLParam(r, "id")
	h.engine.Lock()
	t := h.engine.GetTable(table)
	if t == nil {
		h.engine.Unlock()
		writeJSON(w, 404, map[string]string{"error": "table not found"})
		return
	}
	idCol := h.engine.IDColumn(table)
	for _, row := range t.Rows {
		if fmt.Sprintf("%v", row[idCol]) == id {
			h.engine.Unlock()
			writeJSON(w, 200, row)
			return
		}
	}
	h.engine.Unlock()
	writeJSON(w, 404, map[string]string{"error": "record not found"})
}

func (h *RestAPI) CreateRecord(w http.ResponseWriter, r *http.Request) {
	table := chi.URLParam(r, "table")

	var rec map[string]any
	if err := json.NewDecoder(r.Body).Decode(&rec); err != nil {
		writeJSON(w, 400, map[string]string{"error": "invalid JSON: " + err.Error()})
		return
	}

	h.engine.Lock()
	defer h.engine.Unlock()
	t := h.engine.GetTable(table)
	if t == nil {
		writeJSON(w, 404, map[string]string{"error": "table not found"})
		return
	}

	idCol := h.engine.IDColumn(table)
	if idCol != "" {
		if _, ok := rec[idCol]; !ok {
			rec[idCol] = len(t.Rows) + 1
		}
	}

	t.Rows = append(t.Rows, rec)
	if err := h.engine.Flush(); err != nil {
		writeJSON(w, 503, map[string]string{"error": "flush failed: " + err.Error()})
		return
	}
	writeJSON(w, 201, rec)
}

func (h *RestAPI) UpdateRecord(w http.ResponseWriter, r *http.Request) {
	table := chi.URLParam(r, "table")
	id := chi.URLParam(r, "id")

	var rec map[string]any
	if err := json.NewDecoder(r.Body).Decode(&rec); err != nil {
		writeJSON(w, 400, map[string]string{"error": "invalid JSON: " + err.Error()})
		return
	}

	h.engine.Lock()
	defer h.engine.Unlock()
	t := h.engine.GetTable(table)
	if t == nil {
		writeJSON(w, 404, map[string]string{"error": "table not found"})
		return
	}

	idCol := h.engine.IDColumn(table)
	for i, row := range t.Rows {
		if fmt.Sprintf("%v", row[idCol]) == id {
			for k, v := range rec {
				t.Rows[i][k] = v
			}
			if err := h.engine.Flush(); err != nil {
				writeJSON(w, 503, map[string]string{"error": "flush failed: " + err.Error()})
				return
			}
			writeJSON(w, 200, t.Rows[i])
			return
		}
	}
	writeJSON(w, 404, map[string]string{"error": "record not found"})
}

func (h *RestAPI) DeleteRecord(w http.ResponseWriter, r *http.Request) {
	table := chi.URLParam(r, "table")
	id := chi.URLParam(r, "id")
	h.engine.Lock()
	defer h.engine.Unlock()
	t := h.engine.GetTable(table)
	if t == nil {
		writeJSON(w, 404, map[string]string{"error": "table not found"})
		return
	}

	idCol := h.engine.IDColumn(table)
	for i, row := range t.Rows {
		if fmt.Sprintf("%v", row[idCol]) == id {
			t.Rows = append(t.Rows[:i], t.Rows[i+1:]...)
			if err := h.engine.Flush(); err != nil {
				writeJSON(w, 503, map[string]string{"error": "flush failed: " + err.Error()})
				return
			}
			writeJSON(w, 204, nil)
			return
		}
	}
	writeJSON(w, 404, map[string]string{"error": "record not found"})
}

type responseWriter struct {
	http.ResponseWriter
	status int
}

func (rw *responseWriter) WriteHeader(code int) {
	rw.status = code
	rw.ResponseWriter.WriteHeader(code)
}

func writeJSON(w http.ResponseWriter, status int, data any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if data != nil {
		json.NewEncoder(w).Encode(data)
	}
}