package server

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

	"github.com/xuri/excelize/v2"
	"odoo-go/pkg/orm"
)

// exportField describes a field in an export request.
type exportField struct {
	Name  string `json:"name"`
	Label string `json:"label"`
}

// exportData holds the parsed and fetched data for an export operation.
type exportData struct {
	Model      string
	FieldNames []string
	Headers    []string
	Records    []orm.Values
}

// parseExportRequest parses the common request/params/env/search logic shared by CSV and XLSX export.
func (s *Server) parseExportRequest(w http.ResponseWriter, r *http.Request) (*exportData, error) {
	var req JSONRPCRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		s.writeJSONRPC(w, nil, nil, &RPCError{Code: -32700, Message: "Parse error"})
		return nil, err
	}

	var params struct {
		Data struct {
			Model  string        `json:"model"`
			Fields []exportField `json:"fields"`
			Domain []interface{} `json:"domain"`
			IDs    []float64     `json:"ids"`
		} `json:"data"`
	}
	if err := json.Unmarshal(req.Params, &params); err != nil {
		s.writeJSONRPC(w, req.ID, nil, &RPCError{Code: -32602, Message: "Invalid params"})
		return nil, err
	}

	uid := int64(1)
	companyID := int64(1)
	if sess := GetSession(r); sess != nil {
		uid = sess.UID
		companyID = sess.CompanyID
	}

	env, err := orm.NewEnvironment(r.Context(), orm.EnvConfig{
		Pool: s.pool, UID: uid, CompanyID: companyID,
	})
	if err != nil {
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return nil, err
	}
	defer env.Close()

	rs := env.Model(params.Data.Model)

	var ids []int64
	if len(params.Data.IDs) > 0 {
		for _, id := range params.Data.IDs {
			ids = append(ids, int64(id))
		}
	} else {
		domain := parseDomain([]interface{}{params.Data.Domain})
		found, err := rs.Search(domain, orm.SearchOpts{Limit: 10000})
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return nil, err
		}
		ids = found.IDs()
	}

	var fieldNames []string
	var headers []string
	for _, f := range params.Data.Fields {
		fieldNames = append(fieldNames, f.Name)
		label := f.Label
		if label == "" {
			label = f.Name
		}
		headers = append(headers, label)
	}

	var records []orm.Values
	if len(ids) > 0 {
		records, err = rs.Browse(ids...).Read(fieldNames)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return nil, err
		}
	}

	if err := env.Commit(); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return nil, err
	}

	return &exportData{
		Model: params.Data.Model, FieldNames: fieldNames, Headers: headers, Records: records,
	}, nil
}

// handleExportCSV exports records as CSV.
// Mirrors: odoo/addons/web/controllers/export.py ExportController
func (s *Server) handleExportCSV(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	data, err := s.parseExportRequest(w, r)
	if err != nil {
		return
	}

	w.Header().Set("Content-Type", "text/csv; charset=utf-8")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s.csv", data.Model))

	writer := csv.NewWriter(w)
	defer writer.Flush()

	writer.Write(data.Headers)
	for _, rec := range data.Records {
		row := make([]string, len(data.FieldNames))
		for i, fname := range data.FieldNames {
			row[i] = formatCSVValue(rec[fname])
		}
		writer.Write(row)
	}
}

// handleExportXLSX exports records as XLSX (Excel).
// Mirrors: odoo/addons/web/controllers/export.py ExportXlsxController
func (s *Server) handleExportXLSX(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	data, err := s.parseExportRequest(w, r)
	if err != nil {
		return
	}

	f := excelize.NewFile()
	sheet := "Sheet1"

	headerStyle, _ := f.NewStyle(&excelize.Style{
		Font: &excelize.Font{Bold: true},
	})
	for i, h := range data.Headers {
		cell, _ := excelize.CoordinatesToCellName(i+1, 1)
		f.SetCellValue(sheet, cell, h)
		f.SetCellStyle(sheet, cell, cell, headerStyle)
	}

	for rowIdx, rec := range data.Records {
		for colIdx, fname := range data.FieldNames {
			cell, _ := excelize.CoordinatesToCellName(colIdx+1, rowIdx+2)
			f.SetCellValue(sheet, cell, formatCSVValue(rec[fname]))
		}
	}

	w.Header().Set("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s.xlsx", data.Model))
	f.Write(w)
}

// formatCSVValue converts a field value to a CSV string.
func formatCSVValue(v interface{}) string {
	if v == nil || v == false {
		return ""
	}
	switch val := v.(type) {
	case string:
		return val
	case bool:
		if val {
			return "True"
		}
		return "False"
	case []interface{}:
		// M2O: [id, "name"] → "name"
		if len(val) == 2 {
			if name, ok := val[1].(string); ok {
				return name
			}
		}
		return fmt.Sprintf("%v", val)
	default:
		return fmt.Sprintf("%v", val)
	}
}