package datamodel

import (
    _ "embed"
    "encoding/json"
    "errors"
    "fmt"
    "github.com/daveshanley/vacuum/utils"
    "gopkg.in/yaml.v3"
    "strings"
)

const (
    OAS2  = "oas2"
    OAS3  = "oas3"
    OAS31 = "oas3_1"
)

//go:embed schemas/oas3-schema.json
var OpenAPI3SchemaData string

//go:embed schemas/swagger2-schema.json
var OpenAPI2SchemaData string

var OAS3_1Format = []string{OAS31}
var OAS3Format = []string{OAS3}
var OAS3AllFormat = []string{OAS3, OAS31}
var OAS2Format = []string{OAS2}
var AllFormats = []string{OAS3, OAS31, OAS2}

// ExtractSpecInfo will look at a supplied OpenAPI specification, and return a *SpecInfo pointer, or an error
// if the spec cannot be parsed correctly.
func ExtractSpecInfo(spec []byte) (*SpecInfo, error) {

    var parsedSpec yaml.Node

    specVersion := &SpecInfo{}
    specVersion.jsonParsingChannel = make(chan bool)

    // set original bytes
    specVersion.SpecBytes = &spec

    runes := []rune(strings.TrimSpace(string(spec)))
    if len(runes) <= 0 {
        return specVersion, errors.New("there are no runes in the spec")
    }

    if runes[0] == '{' && runes[len(runes)-1] == '}' {
        specVersion.SpecFileType = "json"
    } else {
        specVersion.SpecFileType = "yaml"
    }

    err := yaml.Unmarshal(spec, &parsedSpec)
    if err != nil {
        return nil, fmt.Errorf("unable to parse specification: %s", err.Error())
    }

    specVersion.RootNode = &parsedSpec

    _, openAPI3 := utils.FindKeyNode(utils.OpenApi3, parsedSpec.Content)
    _, openAPI2 := utils.FindKeyNode(utils.OpenApi2, parsedSpec.Content)
    _, asyncAPI := utils.FindKeyNode(utils.AsyncApi, parsedSpec.Content)

    parseJSON := func(bytes []byte, spec *SpecInfo) {
        var jsonSpec map[string]interface{}

        // no point in worrying about errors here, extract JSON friendly format.
        // run in a separate thread, don't block.

        if spec.SpecType == utils.OpenApi3 {
            spec.APISchema = OpenAPI3SchemaData
        }
        if spec.SpecType == utils.OpenApi2 {
            spec.APISchema = OpenAPI2SchemaData
        }

        if utils.IsYAML(string(bytes)) {
            yaml.Unmarshal(bytes, &jsonSpec)
            jsonData, _ := json.Marshal(jsonSpec)
            spec.SpecJSONBytes = &jsonData
            spec.SpecJSON = &jsonSpec
        } else {
            json.Unmarshal(bytes, &jsonSpec)
            spec.SpecJSONBytes = &bytes
            spec.SpecJSON = &jsonSpec
        }
        spec.jsonParsingChannel <- true
        close(spec.jsonParsingChannel)
    }
    // check for specific keys
    if openAPI3 != nil {
        specVersion.SpecType = utils.OpenApi3
        version, majorVersion := parseVersionTypeData(openAPI3.Value)

        // parse JSON
        go parseJSON(spec, specVersion)

        // double check for the right version, people mix this up.
        if majorVersion < 3 {
            specVersion.Error = errors.New("spec is defined as an openapi spec, but is using a swagger (2.0), or unknown version")
            return specVersion, specVersion.Error
        }
        specVersion.Version = version
        specVersion.SpecFormat = OAS3
    }
    if openAPI2 != nil {
        specVersion.SpecType = utils.OpenApi2
        version, majorVersion := parseVersionTypeData(openAPI2.Value)

        // parse JSON
        go parseJSON(spec, specVersion)

        // I am not certain this edge-case is very frequent, but let's make sure we handle it anyway.
        if majorVersion > 2 {
            specVersion.Error = errors.New("spec is defined as a swagger (openapi 2.0) spec, but is an openapi 3 or unknown version")
            return specVersion, specVersion.Error
        }
        specVersion.Version = version
        specVersion.SpecFormat = OAS2
    }
    if asyncAPI != nil {
        specVersion.SpecType = utils.AsyncApi
        version, majorVersion := parseVersionTypeData(asyncAPI.Value)

        // parse JSON
        go parseJSON(spec, specVersion)

        // so far there is only 2 as a major release of AsyncAPI
        if majorVersion > 2 {
            specVersion.Error = errors.New("spec is defined as asyncapi, but has a major version that is invalid")
            return specVersion, specVersion.Error
        }
        specVersion.Version = version
        // TODO: format for AsyncAPI.

    }

    if specVersion.SpecType == "" {

        // parse JSON
        go parseJSON(spec, specVersion)

        specVersion.Error = errors.New("spec type not supported by vacuum, sorry")
        return specVersion, specVersion.Error
    }

    return specVersion, nil
}

func parseVersionTypeData(d interface{}) (string, int) {
    r := []rune(strings.TrimSpace(fmt.Sprintf("%v", d)))
    return string(r), int(r[0]) - '0'
}

// AreValuesCorrectlyTyped will look through an array of unknown values and check they match
// against the supplied type as a string. The return value is empty if everything is OK, or it
// contains failures in the form of a value as a key and a message as to why it's not valid
func AreValuesCorrectlyTyped(valType string, values interface{}) map[string]string {
    var arr []interface{}
    if _, ok := values.([]interface{}); !ok {
        return nil
    }
    arr = values.([]interface{})

    results := make(map[string]string)
    for _, v := range arr {
        switch v.(type) {
        case string:
            if valType != "string" {
                results[v.(string)] = fmt.Sprintf("enum value '%v' is a "+
                    "string, but it's defined as a '%v'", v, valType)
            }
        case int64:
            if valType != "integer" && valType != "number" {
                results[fmt.Sprintf("%v", v)] = fmt.Sprintf("enum value '%v' is a "+
                    "integer, but it's defined as a '%v'", v, valType)
            }
        case int:
            if valType != "integer" && valType != "number" {
                results[fmt.Sprintf("%v", v)] = fmt.Sprintf("enum value '%v' is a "+
                    "integer, but it's defined as a '%v'", v, valType)
            }
        case float64:
            if valType != "number" {
                results[fmt.Sprintf("%v", v)] = fmt.Sprintf("enum value '%v' is a "+
                    "number, but it's defined as a '%v'", v, valType)
            }
        case bool:
            if valType != "boolean" {
                results[fmt.Sprintf("%v", v)] = fmt.Sprintf("enum value '%v' is a "+
                    "boolean, but it's defined as a '%v'", v, valType)
            }
        }
    }
    return results
}

// CheckEnumForDuplicates will check an array of nodes to check if there are any duplicates.
func CheckEnumForDuplicates(seq []*yaml.Node) []*yaml.Node {
    var res []*yaml.Node
    seen := make(map[string]*yaml.Node)

    for _, enum := range seq {
        if seen[enum.Value] != nil {
            res = append(res, enum)
            continue
        }
        seen[enum.Value] = enum
    }
    return res
}